With the development in mobile communication and wireless communication technologies, location information on mobile terminals and wireless terminals has become important. The location information of the terminal can be applied in various services. For example, a location finding service can be provided to find a variety of convenient facilities around a current location by using terminal positioning identification. Further, a location of a user or a friend can be found by examining a location of a target to be tracked. Furthermore, in businesses such as sales, insurance, call taxi, etc., a person or a vehicle which travels can be effectively deployed or managed by using the location information of the terminal. In addition, it can be used to inform guardians of current locations or movement paths of those who need care, such as, children, seniors, people with disabilities, etc. It can be also used to deal with accidents or disasters in an emergency situation. It can be also used to provide a user with traffic information, map information, and location information of surroundings according to a current location of a mobile terminal user. It can be also used to provide a variety of information regarding leisure facilities (e.g., amusement parks, tourist attractions, etc.).
In addition, in the wireless communication system, data can be reliably transmitted by using the geo-location information of the terminal before a base station (BS) schedules specific data traffic for the terminal. For example, in a cognitive radio (CR) system, BSs and terminals have to sense permitted frequency bands currently being used and perform communication by checking whether the frequency bands are permitted. In this case, if the CR system can know the geo-locations of the terminals in advance, it can determine connectivity of the terminals by using a specific time-frequency resource according to a specific spectrum policy without having to sense the permitted frequency bands. In addition, the location information of the terminal can be used to effectively schedule power and carriers for the terminals so that interference can be optimally minimized in the CR system itself. The location information of the terminal can also be used to estimate a level of interference towards coexisting wireless communication systems and to properly control power of terminals and scheduling.
At present, a location tracking function of a terminal can be implemented according to a method of using a cell location registered in a home location register (HLR) or a method of using location information based on a global positioning system (GPS). The method of using location information based on the GPS has a disadvantage in that the terminal needs to have an additional GPS function. The method of using cell location registered to the HLR without the GPS function has a disadvantage in that the location of the terminal cannot be accurately estimated. That is, a specific cell, in which the terminal is located, can be known whereas an exact location of that cell cannot be known.
In the CR system, a terminal, which is fixed in location during a call but is movable before and after the call, may coexist with a wired terminal which is fixed in location for a long period of time. A process of estimating a level of interference towards coexisting wireless communication systems is performed independently from a process of estimating the location of the terminal. That is, when the interference level is estimated, the location information of the terminal is provided according to a location estimation process which is defined to use the location information of the terminal. The provided location information of the terminal is simply obtained from a database such as the HLR. Therefore, the interference level cannot be accurately estimated since a movement state of the terminal is not taken into account.